I have a 98 4l80e with 40k on it that came out of a wrecked truck..it takes its time going into forward and reverse and has a whining noise going thru the gears...I just put it in and top'd the trans fluid off and haven't changed the filter or fluid yet.. don't know if that would cause the delay going into gear are not..any help will be appreciated.. thanks

 

Anytime you install a used transmission always change fluid and filter. You should do this before to help judge the condition of the trans.